Search for a new heavy scalar particle decaying into a Higgs boson and a new scalar singlet in final states with one or two light leptons and a pair of τ-leptons with the ATLAS detector

Beck, H.P.; Chatterjee, M.; Dal Santo, D.; Halser, L.; Mobius, S.; Müller, R.; O'Neill, A.P.; Schefer, M.M.; Weber, M.S. (2023). Search for a new heavy scalar particle decaying into a Higgs boson and a new scalar singlet in final states with one or two light leptons and a pair of τ-leptons with the ATLAS detector. Journal of High Energy Physics, 2023(10) Springer 10.1007/JHEP10(2023)009

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A search for a new heavy scalar particle X decaying into a Standard Model (SM) Higgs boson and a new singlet scalar particle S is presented. The search uses a proton-proton (pp) collision data sample with an integrated luminosity of 140 fb−1 recorded at a centre-of-mass energy of √s = 13 TeV with the ATLAS detector at the Large Hadron Collider. The most sensitive mass parameter space is explored in X mass ranging from 500 to 1500 GeV, with the corresponding S mass in the range 200–500 GeV. The search selects events with two hadronically decaying τ-lepton candidates from H → τ+τ− decays and one or two light leptons (ℓ = e, μ) from S → VV (V = W, Z) decays while the remaining V boson decays hadronically or to neutrinos. A multivariate discriminant based on event kinematics is used to separate the signal from the background. No excess is observed beyond the expected SM background and 95% confidence level upper limits between 72 fb and 542 fb are derived on the cross-section σ(pp → X → SH) assuming the same SM-Higgs boson-like decay branching ratios for the S → VV decay. Upper limits on the visible cross-sections σ(pp → X → SH → WWττ) and σ(pp → X → SH → ZZττ) are also set in the ranges 3–26 fb and 6–33 fb, respectively.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)
10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)

UniBE Contributor:

Beck, Hans Peter, Chatterjee, Meghranjana, Dal Santo, Daniele, Halser, Lea, Möbius, Silke, Müller, Roman, O'Neill, Aaron Paul, Schefer, Meinrad Moritz, Weber, Michele

Subjects:

500 Science > 530 Physics

ISSN:

1029-8479

Publisher:

Springer

Language:

English

Submitter:

BORIS Import LHEP

Date Deposited:

31 Jan 2024 16:47

Last Modified:

30 Jun 2024 02:19

Publisher DOI:

10.1007/JHEP10(2023)009

Additional Information:

Kollaboration - Es sind nur die Berner Autor*innen namentlich erwaehnt; the ATLAS collaboration

Uncontrolled Keywords:

Hadron-Hadron Scattering

BORIS DOI:

10.48350/191812

URI:

https://boris.unibe.ch/id/eprint/191812

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